Head portion of a toothbrush



FIG. 1 is a right front perspective view of a head portion of a toothbrush according to the new design;

FIG. 2 is a left front perspective view thereof;

FIG. 3 is a right rear perspective view thereof;

FIG. 4 is a left rear perspective view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a rear view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a left side view thereof;

FIG. 9 is a top view thereof; and,

FIG. 10 is a bottom view thereof.

All broken lines shown in the drawings are for environmental purposes only and form no part of the claimed design. 

The ornamental design for a head portion of a toothbrush, as shown and described. 